Existing grain dryers commonly utilize a plurality of longitudinally juxtapositioned hexagonal-shaped grain conduits which have a longitudinal central opening that serves as a heat plenum through which hot air is driven by a suitable fan. At least the inner walls of the plenum are perforated to permit the air to access the hexagonal-shaped conduits to dry the grain therein. The grain typically is introduced into the dryer at the top and moves by gravity in a downward direction while it is being dried. The dried grain is discharged into a conventional elongated auger through a discharge port at the bottom of the conduits. The lower ends of the conduits are typically closed except for a horizontal discharge opening at the lower ends thereof. A horizontal paddle wheel or feed metering roll is mounted adjacent the discharge opening. Its rotation facilitates the movement of the dried grain out of the conduits.
While these existing grain dryers are effective in drying grain, they suffer at least one shortcoming in that the grain adjacent the wall of the conduit that is in common with the heat plenum often becomes quite hot and the grain in that layer is damaged. The damage usually is reflected by stress cracks in grain which results in inferior quality. That hotter layer is dryer than the remaining wetter grain in the conduit. When the very dry grain is subsequently mixed with the wetter grain, a non-uniform quality of the mixed grain results.
It is therefore a principal object of this invention to provide a method and apparatus for drying grain in such a conventional dryer wherein the quality of the grain will be enhanced and the layer of grain against the common wall with the heat plenum will not be damaged by this hotter condition.
A still further object of this invention is to move the layer of grain along the plenum wall more quickly to reduce its temperature and relative degrees so that a more uniform quality of mixed grain is achieved.
These and other objects will be apparent to those skilled in the art.